Interchangeable Jaw Pliers

ABSTRACT

Interchangeable jaw pliers with detachable jaws that are push fit attachable to respective jaw mountings connected with the pliers handles

FIELD OF INVENTION

The invention relates to pliers with interchangeable jaws.

BACKGROUND TO THE INVENTION

Existing locking pliers disclosed by U.S. Pat. No. 9,855,642 (Wu),US2015273664 (Skodje et al) and U.S. Pat. No. 9,855,642 (Wu) comprisetwo handles connected to respective jaws, and a locking mechanismconnected to the two jaws. The handles can be squeezed to close thejaws. A locking member is attached to an over centre linkage, which whenutilized prevents the lower handle from pivoting from its closedconfiguration and until opened retains the jaws in a closed position.The clamping width of the jaws is adjusted by an adjustment screw. Theadjustment screw also determines the clamping pressure exerted upon theclamped workpiece. As the clamping pressure has to be pre-set, it cantake several attempts to correctly adjust the screw to the positionrequired to clamp the workpiece the optimum way. The clamping width ofthe jaws once set by the adjusting screw is finite, so any movement,vibration or relaxing of the clamped material will normally result inthe failure of the clamping action. This is most prevalent when thepliers are used to initially clamp vehicle bodywork parts during a panelbeating process prior to welding or bolting the panels as inadvertentover pressure applied by the clamping jaws usually results in damage ordistortion of the clamped parts.

USD742194 (Engel et al) shows pliers having a toothed strut with alocking mechanism attached to one operating arm. As the arms are closed,the teeth ratchet past the lock. As the operating arms are not designedto resiliently deform, the toothed arc of the strut remains insubstantially the same locking angle relative to the locking mechanism.

EP2818280(Buchanan) discloses pliers having a bowed or arcuate portionto permit limited flexing of one of the handles. A pivotal strut isretained between the handles. A first end of the strut is slidably heldin a channel within one handle and the second end is pivotally heldwithin the other handle. The second end has an arcuate side surfaceprovided with teeth of the strut. The strut acts with a switch and apawl to lock or unlock the handle positions relative to one another. Thecompression of the handles closing the gap between the fixed andmoveable jaws, the moveable jaw sliding up a clamp bar portion until thejaws robustly contact the workpiece, the further operation of thehandles resulting in the clamping of the workpiece, the resilientarcuate portion acting to impose a limited sprung grip upon theworkpiece, further usefulness imported by the locking action of the pawlteeth within the strut arc teeth when the pawl is switched into itsratchet locking position retaining the handles substantially in theirclosed position providing a limited spring grip upon the workpiece. Thearc of the toothed strut in conjunction with the corresponding toothedarc of the pawl being capable of compensating for the changes in anglesof one handle relative to the other as the resilient portion flexes asdiffering pressures are applied to the handles during use, the pawl isactivated into either a locking or non-locking position by a furtherseparate “rocker” switch incorporating a spring and plunger mechanismwhich acts upon the pawl.

It is an object of the present invention to at least partially alleviatethe above-mentioned disadvantages, or to provide a cost savingalternative to existing products.

SUMMARY OF THE INVENTION

The invention provides interchangeable jaw pliers as specified in claim1.

Examples of the invention interchangeable jaw pliers comprising a headportion incorporating gripping faces within the opposing jaws for theclamping of the desired workpiece, pivotal handle portions and a pivotalstrut positioned between the handles. Bow shaped resilient portion orportions can be usefully incorporated within either or both the jaw orhandle portions, when the pliers are operated these resilient portionsimpart a useful sprung pressure upon the clamped workpiece by thegripping face of the jaws. The jaws can be usefully locked in therequired clamping position upon the workpiece, in this example by apivotal strut having a first end toothed arc being locked or unlockedaccording to the toothed switch operation within the first handle andhaving a strut second end slidingly engaged within a strut channel inthe opposing second handle by an axle pin. The said opposing or secondhandle having a recess or channel with outer slots for the retention ofthe strut second end axle pin within the said slots, the strut secondend is driven down the second handle channel within the confines of theslots as the handles are closed relative to one another, the pivotingfirst end of the strut the toothed arc, ratcheting against the sprungbiased corresponding switch teeth. In order to provide as versatile aspossible a set of pliers the jaw portions are interchangeable with otherjaw portions the gripping faces can comprise of clamping or grippingprofiles useful for many purposes, metalwork, woodwork and automotive toname but a few, whilst the handle portion within its particular sizerange can be the same incurring a substantial cost and storage saving.

The interchangeable jaw pliers may comprise an intuitive switchlocking/unlocking mechanism utilizing less parts than previous plierstype tools comprising pivotal struts with toothed arcs interacting witha switch. The switch usefully now directly incorporates a single piecelocking, ratcheting or disengaged teeth mechanism according to itschosen orientation, which can be usefully utilized as required to engagewith the teeth of the toothed strut arc to positionally to lock asrequired the same, thereby locking the clamped workpiece within the jawportions, or alternately disengaging the switch teeth from the struttoothed arc releasing the workpiece from the jaws, according to thepivotal switch orientation.

The switch may incorporate a ratchet function, the switch usefullyincorporating a bore for the engagement of a biasing pin and itscompression spring, said biasing pin being free to move lengthwisewithin said bore against the resilient force of the spring. In bestpractice the outer end of the biasing pin is rounded or angled with ablunt point for ease of movement against a corresponding peakedengagement profile. Said pin having a close sliding fit within said borewhereas it can easily traverse inwards or outwards against the springwithin said bore according to the engagement between the blunt point andthe corresponding peaked engagement profile mounted within the handle.Said switch engagement profile further comprising of a transition peakwith a sloping open profile on one side and a switch closing profile onthe other, the pivotal switch can be manually intuitively operated bythe operator from either chosen position, during said switch positionaloperation said biasing pin is resiliently propelled into the switch boreagainst the incumbent spring as its outward blunt point moves againstthe corresponding upwardly sloping engagement profile till it traversesthe peak of the engagement profile and consequently now engages thedownwardly sloping engagement profile at the other side of the peak, theswitch spring usefully resiliently propelling the biasing pin bluntoutward end against its corresponding sloping engagement profilepositively resiliently engaging or disengaging the switch teeth from thetoothed strut arc teeth according to the operators requirements.

As it is commercially prudent to have a ratchet like clicking noise toaccompany the jaw closure and locking procedure the interaction of theresiliently biased switch teeth with the corresponding pivotal struttoothed arc teeth, when the switch is in the closed position provides atypical ratchet like sound as the strut rotates during the closureprocedure around the strut axle against the resilience of the strutspring.

The interchangeable jaw pliers may provide clamping widths within itsspecification that are automatically adjusted, the locking pressure canbe further be usefully determined by the operator by the straightforwardgripping pressure of the handles, the simple release of the handles whenthe switch is in the closed position initiating the locking if requiredof the jaws upon the clamped parts. The operator defining the option ofthe device being in the locking or unlocked mode by the positioning ofsaid switch. The clamping action of said jaws being determined by theremaining resilience of the bowed portions, the elastic potentialenergy. The resultant jaw resilient closing force is largelyproportional to the force applied to the handles and the pivotaldimension ratio between the handles and jaws less any small lossesincurred during the switch locking procedure, the fulcrum being the jawpivot pin.

The invention also includes, in a further iteration in order to providea more versatile and useful device, a method whereby the jaw workingprofiles or outer jaw can be interchanged with other outer jaws withdiffering working profiles in order to provide a cost-effectiveequivalent to several set of differing pliers required for differentjobs. These interchangeable jaws being usefully locked or unlocked fromrobust engagement within the lower jaws as required, providing onelocking handle set capable of use with a cost-effective range ofdiffering jaws as required.

In one example the lower jaws comprising of a laminate like constructionin order to provide a low-cost method of retaining the locking swivelpin which comprises a central axle rotatable within a correspondingthickness and bore within the lower jaw inner plate. The locking swivelpin having a further reduced circumference hereafter termed outer axles,largely level in height to the lower jaw outer plates which havecorresponding circular cut out profiles such that the said swivel pin islaterally held within the lower jaw by the outer plates whilst capableof rotation within its afforded enclave. The outer end face of thelocking swivel pin can usefully incorporate a small lever for therequired operator rotation of the said pin. The locking swivel pin outeraxles comprising a spherical locking face and a generally flat unlockingface, the spherical locking face can be further appropriately cam shapedin order to increase the locking mechanism proficiency. The lockingswivel pin is located partially within the lower jaw interlocking tonguerecess, by rotating the locking swivel pin the profile of the lockingswivel pin outer axle can be chosen to either present a locking orunlocking face into the tongue recess. The detachable outer jaws havingcorresponding locking tongues incorporated within their generally planarouter plates, in best practice the tongues are formed in a slow curve toaid their robust engagement within the matching tongue recesses. Whenthe chosen outer jaw tongues are fully inserted within their lower jawrecesses, the lower jaw abutment faces further robustly contact theouter jaw abutment faces. The tongues having suitably positionedindentations for the engagement of the outer axle locking faces when thelocking switch axle is appropriately utilized, conversely the lockingswitch axles can be suitably rotated wherein the unlocking faces of thesaid switch axle are substantially in line with the profile of the jawinterlocking tongue indentations in order to provide straightforwardengagement or withdrawal of the chosen outer jaw from the lower jaw.

The interchangeable jaws pliers may comprise first and second lower jawshaving strong permanent magnets fitted such that their magnetic fieldcan suitably act on the metal leading end of the interlocking tongueportions, the said magnets magnetic force robustly locking thedetachable jaw or jaws in place within the said lower jaws, in order toremove a detachable jaw the operator requires to open the jaws andforcefully pull the detachable jaw from the interlocking tongue recess.This construction allows the first and second lower jaw portions to bemore cost effectively formed in one piece such as an investment castingwithout the requirement of separate outer cover plates.

In some examples, the said strut second end being in a generallycylindrical form whereas during assembly said strut can be rotatedwhereby the second end pin can be usefully inserted into the secondhandle strut channel, rotated until the second end axle pin engages intothe strut end retention slots and the assembly continued, thisconstruction allows the second handle to be formed in one piece such asan investment casting without the requirement of second handle outerplates or a separate cover plate.

In some examples, there is no handle bowed resilient portionincorporated, the pliers operation still incorporating interchangeablejaws or being switchable between locking and unlocking of the handles.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be well understood, some examples willbe described with reference to the drawings, in which:

FIG. 1 is a perspective view of the interchangeable jaw pliers;

FIG. 2 is a plan view of the interchangeable jaw pliers;

FIG. 3 is an enlargement of the circled portion of FIG. 2;

FIG. 4 is a plan view of the interchangeable jaw pliers with a partshown in section;

FIG. 5 is an enlargement of the sectioned part of FIG. 4;

FIG. 6 is a view corresponding to FIG. 5 showing an alternativeposition;

FIG. 7 is a perspective view of the interchangeable jaw pliers showing aworkpiece clamped by the pliers;

FIG. 8 is an exploded perspective view of the interchangeable jawpliers;

FIG. 9 is an exploded perspective view of a detachable jaw of theinterchangeable jaw pliers;

FIG. 10 shows a handle and pivotal strut of the interchangeable jawpliers; and

FIG. 11 is a perspective view of another interchangeable jaw pliers.

DETAILED DESCRIPTION

FIG. 1 shows interchangeable jaw pliers 1 at rest. The interchangeablejaw pliers 1 comprises a head portion 200 and a handle portion 300. Thehandle portion 300 comprises a first handle 301 and a second handle 302and respective first and second jaw mountings 208. 209 at one end. Thehead portion 200 comprises detachable jaws 205 that have respectivetongue portions 218. The jaw mountings 208, 209 may be provided withrespective jaw locking switches 603. A jaw pivot pin 600 may be providedto permit relative pivoting movement of the first and second handles301, 202. The first and second handles 301, 302 may comprise a laminatestructure. For example, the first handle 301 may comprise top and bottomplates 309 (FIG. 7) that define the outer major faces of the handle.Similarly, the second handle 302 may comprise top and bottom plates 311(FIG. 7) that define the outer major faces of the handle.

FIG. 2 shows the interchangeable jaw pliers 1 with the top plates 309,314 removed from the first and second handles 301, 302 to illustrate apivotal strut 400, a pivotal switch 500 and switch cam block 509. Thepivotal switch 500 is shown in a disengaged position. The detachablejaws 205 are shown comprising gripping faces 203 and abutment faces 220.The first and second jaw mountings are shown provided with assemblyholes 204 and fixings 602.

FIG. 3 shows the pivotal switch 500 in its unlocked position. In thisposition, the actuating end 507 of the switch biasing pin 506 is engagedwith an open profile 510 of the switch cam block 509 ensuring that theswitch locking teeth 503 provided on the pivotal switch 500 aredisengaged from the strut teeth 402.

FIGS. 4 and 5 show the interchangeable jaw pliers 1 with the top plates309, 314 of the first and second handles 301, 302 removed to illustratethe pivotal strut 400, pivotal switch 500 and switch cam block 509. Thepivotal switch 500 is shown in section to illustrate a switched lockingmechanism, which can be operated to cause the switch locking teeth 503to engage the strut teeth 402. <The strut teeth 402 may be provided onan arcuate side, or edge, surface 401 of the pivotal strut 400> topositionally lock a clamped workpiece 80 between the detachable jaws205. The pivotal switch 500 can also be operated to cause the switchlocking teeth 503 from the strut teeth 402 to release the workpiece 80from the detachable jaws 205. FIG. 4 indicates a clenching force Capplied to the handle gripping portions 303 to squeeze the first andsecond handles 301, 302 to cause the workpiece 80 to be clamped betweenthe detachable jaws 205. An axle 405 is held within the retention slots317 with a further strut end contact surface 316 available. The firstand second handles 301, 302 when operated to move the detachable jaws205 together act against a spring 70 connected between a springattachment hole 406 and a spring attachment portion 222 provided on thefirst handle 301. The spring 70 acts to bias the first and secondhandles 301, 302 towards an open position when the pivotal switch 500 isin an unlocked position. The switch spring 71 biases the biasing pin 506so that the actuating end 507 of the biasing spring 56 is pressedagainst the closing profile 511 of the switch cam block 509 as thehandle portion 300 is operated to clamp the workpiece 80. Theresiliently biased biasing pin 506 acts to provide a ratchet actionbetween the switch locking teeth 503 and the strut teeth 402 as thepivotal strut 400 is pivoted by its second end 403 interacting with thehandle strut end contact surface 316. The pivotal strut 400 is retainedby the strut second end axle 405 within the retention slots 317. Thestrut teeth 402 and the switch locking teeth 503 may have a saw toothconfiguration, or profile, to provide an extra safety locking feature,whereby the pivotal switch 500 when moved to an unlocked position stillrequires the clenching, or squeezing together, of the first and secondhandles 301, 302 to disengage the switch locking teeth 503 from thestrut teeth 402 to release the gripping force applied to the workpiece80.

FIG. 5 shows the pivotal switch 500 in its locked position. The switchbiasing pin 506 actuating end 507 is shown engaged with the closingprofile 511 on the switch cam block 509 to ensure that the switchlocking teeth 503 are pushed towards, or into, the strut teeth 402 onthe pivotal struct 400. Further illustrated are the pivotal switch axle501, biasing pin bore 504, actuator 505, biasing pin 506, biasing pinactuating end 507, biasing pin spring abutment face 508, switch spring71, open profile 510 and cam block transition profile 512 of anengagement profile 510, 511, 512 provided on the switch cam block 509.

As shown in FIG. 6 the pivotal switch 500 may incorporate ratchetfunctionality. The pivotal switch 500 has a bore 504 that houses abiasing pin 506 and a biasing compression spring 71. The biasing pin 506is free to move in a lengthwise direction of the bore 504 against theresilient force of the spring 71. The actuating end 507 of the biasingpin 506 is rounded or angled with a blunt point for ease of movementagainst a peaked engagement profile 510, 511, 512. The biasing pin 506is a close sliding fit within the bore 504, which is configured to allowthe biasing pin 506 to easily move back and forth in the bore 504according to the engagement between the actuating end 507 and theengagement profile 510, 511, 512. The engagement profile 510, 511, 512is defined by a cam surface of the switch cam block 509, which maydefine a recess in a side of the switch cam block. The engagementprofile comprises a transition peak 512 with a sloping open profile 510on one side and a switch closing profile 511 on the other. The pivotalswitch 500 can be manually moved using the switch actuator 505. Duringoperation of the pivotal switch 500, the biasing pin 506 is pushed intothe switch bore 504 against the compression spring 71 as the actuatingend 507 moves against the corresponding upwardly sloping engagementprofile 510, 511 till it traverses the peak of the engagement profile512 and consequently now engages the chosen downwardly slopingengagement profile at the other side of the peak 510, 511. The switchspring 71 resiliently biases the actuating end 507 against theengagement profile 510, 511 to positively resiliently hold the switchlocking teeth 503 in respective positions in which the switch lockingteeth 503 are engaged with or disengaged from the strut teeth 502.

The switch spring 71 is further utilized to directly cause the switchteeth 503 to act in a ratcheting manner against the strut teeth 402 whenthe switch 500 is operated in the locked position and the pivotal strut400 is pivoted around the strut axle 405 as the handles 301, 302 areclenched.

The switch cam block 509 may be incorporated into a handle spacer 305 orhandle 301, 302 assembly.

FIG. 7 illustrates the interchangeable jaws 1 with the gripping faces203 of the detachable jaws 205 clamped G upon a workpiece 80. Handlebend promoting portions 304 providing resilient gripping G of thedetachable jaws 205 on the workpiece 80 when a clenching, or squeezing,force applied to the handles 301, 302 is released. The gripping force ismaintained by the engagement of the switch locking teeth with the strutteeth 402. As indicated in FIG. 7, the locked pivotal strut 400comprises the base and the bend promoting portions 304 comprise thesides of triangular elastic potential energy structure A. The jaw pivotpin 600 forms the apex of the triangle, with the pivotal switch axle 501forming another corner. The axle 405 at the second end 403 of thepivotal strut 400 acts via the detachable jaws 205 to apply clampingpressure upon the workpiece 80, this clamping force G beingadvantageously resilient in nature. Further illustrated are the secondhandle strut channel 306, strut pivot pin hole 307, switch pivot pinhole 308, first handle outer and inner plates 309, 310, second handleouter and inner plates 314, 315.

FIG. 8 illustrates the Replaceable jaw pliers 1 head portion 200 first201 and second 202 jaw portions, with one version of detachable jaw 205shown disengaged, comprising gripping faces 203, first lower jaw 208,second lower jaw 209, inner plate 210, said outer plate 211, lower jawweb 212, detachable jaw 205, interlocking tongue 218, interlockingtongue indentations 219, abutment faces 220, lower jaw abutment faces214, detachable jaw engagement slots 215, detachable jaw outer plate 217and inner plate 216. Jaw locking switch 603, operating lever 605 and jawswitch unlocking face 606. The pivotal strut 400, second end axle 405 isfurther shown within the strut end retention slot 317, the pivotalswitch 500 actuator 505 is illustrated within the first handle portion301. In this laminated example the handles 301, 302 and said lower anddetachable jaws 205 are held together by fixings 602 through assemblyholes 204, 213, 306.

FIG. 9 shows an example of a laminated detachable jaw 205 in adismantled condition. The detachable jaws 205 comprise outer plates 217,inner plate 216, gripping faces 203, blade members that form the tongueportions 218, with indentations 219, abutment faces 220 and fixing holes213 for fixings 602. Also shown in FIG. 9 are a pair of jaw lockingswitches 603. Each locking switch 603 comprises a locking switch axle604, outer retaining axles 608, 609, switch locking face 607, switchunlocking face 606 and a switch operating lever 605.

FIG. 10 illustrates a non-laminate second handle 302 comprising a secondhandle strut channel 306, retention slots 317 for the second end of thepivotal strut 400 and second jaw mounting 209 made in one piece. Thesecond end 403 of the pivotal strut 400 may have a generally cylindricalform 407. During assembly, the pivotal strut 400 can be rotated so thatthe second end axle pin 405 is in a first condition so that it can beinserted into the second handle strut channel 306 and then rotated untilthe second end axle pin 405 engages in the retention slots 317. Thisconstruction allows the second handle 302 to be formed in one piece suchas an investment casting without the requirement of second handle outerplates 314 or a separate cover plate.

FIG. 11 illustrates another example of an interchangeable jaws pliers 1.The handle portion 300 includes no bend promoting portions such as thebend promoting portions 304 shown in FIG. 7. The interchangeable jawpliers 1 may comprise a set of woodwork clamping detachable jaws 205,which are shown detached from the handle portion 300. The first andsecond jaw mountings 208, 209 may be provided with magnet holding slots318 that at least partially house respective jaw retaining permanentmagnets 601. At least the leading edges 221 of the tongue portions 218of the detachable jaws 205 may be made of a ferrous material so thatwhen the detachable jaws 205 are push-fit engaged with the first andsecond jaw mountings 208, 209, the detachable jaws 205 are secured tothe handle portion 300 by magnetic forces. The handles 301, 302 havefirst and second jaw mountings 208, 209 that can be manufactured morecost effectively in fewer pieces by, for example, investment casting.Optionally, the second end 403 of the pivotal strut 400 may have acylindrical section 407. The cylindrical section 407 may be insertedinto the second handle strut channel 306 with the strut second end axle405 extending in the lengthwise direction of the strut channel 306 andthen rotated to engage the axle 405 in the retention slots 317. Thefirst handle 301 preferably uses a switch cover plate 305 fixed by knownmeans as an aid to assembly or servicing.

1. Interchangeable jaw pliers comprising a first handle, a firstdetachable jaw attached to a first jaw mounting disposed at a first endof the first handle, a second handle pivotally connected to the firsthandle to permit relative pivotal movement of said first and secondhandles and a second detachable jaw attached to a second jaw mountingdisposed at a first end of said second handle, wherein said detachablejaws are push-fit attachable to the respective jaw mounting. 2.Interchangeable jaw pliers as claimed in claim 1, wherein saiddetachable jaws comprise an inner end provided with a tongue portionconfigured to push-fit attach to respective mating tongue receivingrecesses of the first and second mountings.
 3. Interchangeable jawpliers as claimed in claim 2, wherein said tongue portions compriseopposed blade members that are spaced apart to define a gap, and thetongue receiving recesses are provided with a blade that is push-fitengageable in the respective gap.
 4. Interchangeable jaw pliers asclaimed in claim 3, wherein said tongue portions and tongue receivingrecesses each have a length and curve along said length such that saidtongue portions are disposed in converging relationship when said tongueportions are fitted in said tongue receiving recesses. 5.Interchangeable jaw pliers as claimed in any one of the precedingclaims, wherein the first and second jaw mountings are provided withrespective permanent magnets and at least the leading ends of saidtongue portions are made of a ferrous material, whereby said detachablejaws are magnetically securable to said first and second jaw mountings.6. Interchangeable jaw pliers as claimed in any one of the precedingclaims, further comprising respective rotatable switches to lock saiddetachable jaws to said first and second jaw mountings. 7.Interchangeable jaw pliers as claimed in claim 2, 3 or 4, furthercomprising respective rotatable switches to lock said detachable jaws tosaid first and second jaw mountings, wherein said tongue portions areprovided with indentations engageable by said rotatable switches to lockthe respective detachable jaw to said first and second jaw mountings. 8.Interchangeable jaw pliers as claimed in any one of the precedingclaims, further comprising: a pivotal strut having a first end providedwith teeth and a second end pivotally attached to said second handle; alocking switch pivotally attached to said first handle; and a biasingpin carried by said locking switch and biased to engage a switch camblock carried by said first handle, wherein said locking switch has atleast one tooth engageable with said teeth provided on said pivotalstrut and said switch cam block defines an engagement condition for saidbiasing pin that allows said locking switch to pivot to allow said atleast one tooth to ratchet over said teeth provided on said pivotalstrut.
 9. Interchangeable Jaw Pliers as claimed claim 8, wherein saidlocking switch comprises a bore housing said biasing pin and acompression spring that biases said biasing pin towards said switch camblock, said biasing pin being free to move lengthwise within said boreagainst the compression spring to engage a cam surface on said switchcam block, said cam surface comprising of a transition profile with anopen profile at a first side of said transition profile and a closingprofile at a second side of said transition profile.
 10. Interchangeablejaw pliers as claimed in any one of claims 1 to 7, wherein saiddetachable jaws are lockable in a clamping position upon the workpieceby a pivotal strut having a toothed first end engageable by teethprovided on a spring biased pivotable locking switch mounted on thefirst handle and a second end slidingly engaged with at least one slotprovided on said second handle, the arrangement being such that whensaid first and second handles are squeezed towards one another, thesecond end of the pivotal strut moves along said at least one slot in adirection away from said detachable jaws and the teeth on the first endof the pivotal strut ratchet against teeth provided on the lockingswitch.
 11. Interchangeable Jaw Pliers as claimed in claim 10, whereinsaid second end of said pivotal strut comprises a generally cylindricalsection provided with a pin to engage said at least one slot wherebyduring assembly said pin can be inserted in a recess provided in saidsecond handle in a first orientation and rotated to a second orientationto engage said at least one slot.
 12. Interchangeable jaw pliers asclaimed in any one of the preceding claims, comprising clamping widthswithin its specification that are automatically adjusted, the lockingpressure can be further be usefully determined by the operator by thestraightforward gripping pressure of the handles, the simple release ofthe handles when the switch is in the closed position initiating thelocking if required of the jaws upon the clamped parts, the operatordefining the option of the device being in the locking or unlocked modeby the positioning of the said switch.
 13. Interchangeable jaw pliers asclaimed in claim 10 or 11, further comprising a spring connected betweensaid pivotal strut and first handle to provide resilient opening of saiddetachable jaws when said locking switch is moved to an unlockingposition.
 14. Interchangeable jaw pliers as claimed in any one of thepreceding claims, wherein at least one of said first and second handlescomprises a bowed resilient portion configured to permit bowing of therespective handle when, in use, said detachable jaws are forced againsta workpiece by squeezing said first and second handles together. 15.Interchangeable jaw pliers as claimed in any one of the precedingclaims, comprising a plurality of sets of said detachable jaws.